Cams have been used on compound bows for some time. Compound bows have opposing limbs extending from a handle portion which house the cam assemblies. Typically, the cam assemblies are rotatably mounted on an axel which is then mounted on a limbs of bow. The compound bows have a bow string attached to the cam which sits in a track and also, generally, two power cables that each sit in a track on a separate component on the cam, and either anchored to the cam or a limb/axel. When a bowstring is pulled to full draw position, the cam is rotated and the power cables are “taken up” on their respective ends to increase energy stored in the bow for later transfer, with the opposing ends “let out” to provide some give in the power cable.
Cam assemblies are designed to yield efficient energy transfer from the bow to the arrow. Some assemblies seek to achieve a decrease in draw force closer to full draw and increase energy stored by the bow at full draw for a given amount of rotation of the cam assembly.
There exists a number of U.S. patents directed to compound bows, including U.S. Pat. No. 7,305,979 issued to Craig Yehle on Dec. 11, 2007. The Yehle patent discloses a cam assembly having a journal for letting out a draw cable causing the cam to rotate and two other journals for take-up mechanism and a let-out mechanism for the two power cables. The Yehle patent requires that the power cables and draw string each sit in a different components and tracks for the take up and let out mechanism to work and to have the efficiencies described therein.
Therefore, a compound bow having a mechanism with fewer tracks is desired because of the advantage in assembly in manufacturing and to increase efficiency in the transfer of energy to propel bows.
Further, an adjustable or modular take-up/let-out mechanism is desired to account for different size draw lengths or other specifications required by the user.